Synchronization algorithms for multiuser filtered multitone (FMT) systems

In this paper we consider the synchronization problem in a filtered multitone (FMT) modulated system. An FMT based system differs from the popular OFDM scheme in the deployment of sub-channel shaping filters. We assume a multiuser uplink scenario where sub-channels are partitioned among the active users. Users are asynchronous such that the received signals experience independent time offsets, carrier frequency offsets, and multipath fading. The approach herein presented is based on the deployment of training sequences. We recover symbol/frame timing and carrier frequency for each active user by exploiting the sub-channel separability with an iterative procedure. Then, we run simple linear sub-channel equalizers with RLS training. The robustness of the scheme in an asynchronous uplink scenario is evaluated.